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https://github.com/c64scene-ar/llvm-6502.git
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d0dbe02fd2
The C and C++ semantics for compare_exchange require it to return a bool
indicating success. This gets mapped to LLVM IR which follows each cmpxchg with
an icmp of the value loaded against the desired value.
When lowered to ldxr/stxr loops, this extra comparison is redundant: its
results are implicit in the control-flow of the function.
This commit makes two changes: it replaces that icmp with appropriate PHI
nodes, and then makes sure earlyCSE is called after expansion to actually make
use of the opportunities revealed.
I've also added -{arm,aarch64}-enable-atomic-tidy options, so that
existing fragile tests aren't perturbed too much by the change. Many
of them either rely on undef/unreachable too pervasively to be
restored to something well-defined (particularly while making sure
they test the same obscure assert from many years ago), or depend on a
particular CFG shape, which is disrupted by SimplifyCFG.
rdar://problem/16227836
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209883 91177308-0d34-0410-b5e6-96231b3b80d8
32 lines
655 B
LLVM
32 lines
655 B
LLVM
; RUN: llc < %s -mtriple=thumbv7-apple-ios -arm-atomic-cfg-tidy=0 | FileCheck %s
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;CHECK-LABEL: foo:
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;CHECK: adds
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;CHECK-NEXT: adc
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;CHECK-NEXT: bx
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;rdar://12028498
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define i32 @foo() nounwind ssp {
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entry:
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%tmp2 = zext i32 3 to i64
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br label %bug_block
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bug_block:
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%tmp410 = and i64 1031, 1647010
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%tmp411 = and i64 %tmp2, -211
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%tmp412 = shl i64 %tmp410, %tmp2
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%tmp413 = shl i64 %tmp411, %tmp2
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%tmp415 = and i64 %tmp413, 1
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%tmp420 = xor i64 0, %tmp415
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%tmp421 = and i64 %tmp412, %tmp415
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%tmp422 = shl i64 %tmp421, 1
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br label %finish
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finish:
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%tmp423 = lshr i64 %tmp422, 32
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%tmp424 = trunc i64 %tmp423 to i32
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ret i32 %tmp424
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}
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